Abstract

We demonstrate that the electrical fixation of holograms recorded in (Sr0.75Ba0.25)Nb2O6 involves local polarization switching; the fixing threshold is found to be nearly the average coercive fieldEc = 970 V/cm, and the minimum fixing time is the polarization switching time. The diffraction efficiency enhancement of fixed holograms is attributed to the photoinduced space charge field's overcancellation by ionic displacements associated with the polarization switching.